Wow!The script name have nothing to identify the table in question.You really like to provide puzzles, do you?Also, please provide the code of DML.GetRetailOrOnlineIndicator(), which seems to be a function you're calling in your insert script.

First thing I see in the plan is Query 6 which shows up as 99% of the cost.

Within Query 6, there is a section that accounts for 96% of the plan cost

I suspect (from the estimated and actual rowcounts and the predicates present in the Index Seek on ExtPAIntelActivationEvent.NCIX_ISOCountrycode which includes a condition; ISOCountryCode <> N'' which does not appear anywhere in the query text) that you have another view, perhaps within the Scalar function, perhaps this "DML.ExtKeyWestRetailOnlineInfo"

I would inspect that view to see if it is optimised for the purpose of this query.